I don't really have any suggestions on what to do. The only thing I can think of is sore gums associated with teething, but then you would think she'd have the same problem with the dummy. I would probably try and speak to a child health nurse about it.
I'm not sure what state your in Tania, but here is the contact number for bottle feeding mums support groups for Qld, maybe they could offer some advice?? Bottle Bubs 07 3264 2947
I know since starting solids with my son he has slowly cut back his intake of milk, but he still will drink it if he's hungry.
Let me know how you go, sorry I'm not much help.